A Beautiful Handcrafted Orrery, A Mechanical Model of the Solar System A daily dose of unique art, culture and technology from around the world. A Beautiful Handcrafted Orrery, A Mechanical Model of the Solar System Designer Ken Condal created a beautiful handcrafted orrery , a mechanical model of the Solar System , from “brass, aluminum, acrylic, corian and exotic woods” with the help of David Clark in 2012. The model includes representations of the planets Mercury, Venus, Earth and the Moon, Mars, Jupiter, and Saturn orbiting a clear orb representing the Sun thanks to a series of gears. The particulars of the project, which took Condal 10 months to complete, are broken down in meticulous detail in a series of blogs over on Condal’s website . Ever since the fourth grade when we made solar systems with coat hangers and styrofoam balls, I’ve wanted to build a more realistic Orrery but was never able to find a design or set of plans that inspired me. Having never worked with gears, I believed that designing my own was far beyond my skill level, but that’s never stopped me before.

Orrery Store|Beautiful orrery for sale|Buy orrery|Build A Model Solar System|orrery shop|Orrery Kit|Scale model of solar system|太陽系模型|Build Orrery|Orrery Model|the best mechanical brass orrery in the world View Cart An orrery is a mechanical device that demonstrates the motions and relative positions of the planets and moons in the Solar System in a heliocentric model. They are typically driven by a motor or a clockwork mechanism with a globe representing the Sun at the centre, and with a planet at the end of each of the arms. An orrery can be seen as a scale model of our solar system, it can range widely in size from hand-held to room-sized.. Though the Greeks had working planetaria, the first orrery that was a planetarium of the modern era was produced in 1704, and one was presented to the Earl of Orrery — whence the name came. History The first modern orrery was made circa 1704 by Thomas Tompion and George Graham.

Graham gave the first model or its design to the celebrated device maker named John Rowley, who lived in London,in order to produce a copy for Prince Eugene of Savoy. Rowley produced another one for his patron Charles Boyle, 4th Earl of Orrery, from which the model took its name. This device was given to Charles' son John as present, later the 5th Earl. Its importance was partially in that mechanical scale models of the solar system and the universe, correctly named planetariums gained the name Orrery. There were planetary models before 1704, indeed according to Roman philosopher Cicero, who was writing in the first century BC, Posidonius made a planetary model. The Antikythera mechanism, which was discovered in 1904 in 42m of water off the Greek island of Antikythera, illustrated the five known planets and the diurnal motions of the sun, moon. The Antikythera mechanism is now considered to be one of the earliest orreries, but was not mentioned in the 1967 Science Museum booklet. For many years The Antikythera mechanism was ignored, because it seemed too complex to be genuine.

It was geocentric, used as a mechanical calculator designed to calculate astronomical positions. In the Western religious teaching of a geocentric universe,the sun rotated around the earth,but Copernicus in De Revolutionibus Orbium Coelestium published in Nuremberg in 1543 challenged this. He found that a heliocentric universe had been proposed by some Greek philosophers. This simplified the apparent epicyclic motions of the planets and make it feasible to represent the planets path as a simple circle, which could be modelled by the use of gears. Tycho Brahe's improved devices made precise observations of the skies (1576–1601), from which Johannes Kepler (1621) proved that planets orbited the sun in ellipses. The cause of this motion was explained in Isaac Newton's theory of gravitation In 1687. Christian Huygens calculated the gear trains which were needed to represent 365.242 days year length, and using which to make the cycles of the principal planets. As late as 1650, P.

Schirleus has made a Geocentric planetarium ,it showed the sun as a planet with Mercury and Venus moving around it as moons. Christian Huygens built a heliocentric planetary model while resident in Paris between 1665 and 1681, and in 1703 he published details of the model. A picture hangs in Derby Museum and Art Gallery named "A Philosopher giving a Lecture on the Orrery in which a lamp is put in place of the Sun" by Joseph Wright (ca. 1766), features three children, three men, and a lone woman, listening to a lecture by a 'natural philosopher'— the only light is from the "sun" in the brass orrery, which, in this case, has rings that cause it to look like an armillary sphere. The demonstration was thereby able to show eclipses. To put this in context, longitude was allowed to be accurately measured by John Harrison's Chronometer in 1762,and also in 1766 Titius first who was an astronomer demonstrated that the mean distance of the planets could be represented by the progression .

That is, 0.4, 0.7, 1.0, 1.6, 2.8, 5.2, 10.0 ... The numbers refer to astronomical units, that is 93 x 10^8 miles(1.496 x 10^8 km). The Derby Orrery doesn't show mean distance, but demonstrated the relative planetary movements: all part of a process understanding contemporary cutting edge scientific thinking. Eisinga's "Planetarium" was made from 1774 to 1781 in his home in Franeker, in the Netherlands. This "Planetarium" displays the planets across the width of a room's ceiling, and has been in operation almost continually since it was built. This orrery was a planetarium in both senses of the word- firstly a complex planetary instrument, and secondly it was displayed in a special room, which was a sort of theatre for observers. the Dutch Royal family, by who gave him a pension, bought Eisinga house. A 1766 Benjamin Martin Orrery, used at Harvard Benjamin Martin created a new type of planetary instrument in 1764.

In this new planetary instrument the planets were carried on brass arms leading from a series of coaxial or concentric tubes. With this construction it was difficult to get the moons to turn around the planets, and to make the planets revolve. Benjamin Martin thought that there were three parts that the conventional orrery should consist of: The lunarium which showed the rotations of the moon around the earth, the tellurian(tellurion) which showed the inclined axis of the earth and how it revolved around the sun, and the planetarium where the planets revolved around the sun. In an orrery, these three motions could be assembled on a common table and separately using the central spindle as a prime mover. Grand Illusions Ltd Grand Illusions Ltd Price:�47.99(Including VAT at 20%) Price: �39.99(Excluding VAT at 20%) Quantity: Orrery Kit This advanced kit allows you to build your own orrery, a mechanical model of the solar system. This version shows the sun, Mercury, Venus, the Moon and Earth.

When you turn the handle, this causes a number of motions to occur : the inner planets Mercury and Venus revolve around the sun; the moon orbits the earth, and the moon and the earth orbit the sun; the axis of the earth remains in the same inclination, which allows us to see how the seasons are caused. The kit comes as a number of sheets of heavy duty, printed and punched card, together with all the accessories. The sun has an internal battery (supplied) and LED lights, and thus lights up. Many celestial processes can be seen. Not only the change of the seasons, but the phases of the moon, and the behaviour in the sky of planets like Venus, which sometimes appear in the morning, and sometimes in the evening. The completed model is 31cm high and 35cm wide. Supplied with full assembly instructions. This is a sophisticated kit, and is recommended for ages 14+.

Made in EU Mechanical Orreries, Planetariums and Telleriums | eBay Mechanical Orreries, Planetariums and Telleriums Share 6 March 2011 Orreries (named for the Earl of Orrery) are mechanical models of the solar system originally intended as educational tools, and also often used as ornaments. They are often called Planetariums. Generally speaking they aren't made to scale - it would be impractical to show orbital distances at anything like true scale, and the giant planets are so large that the small inner planets would be virtually invisible at any practical scale. Antique Orreries can be extremely expensive, but there are many fakes and replicas. Telleriums are models of the Earth, Moon, and Sun; they are typically designed to show the seasons, eclipses, phases of the Moon, etc. I've also included some other models that don't strictly fall into either category, but may be of interest. It should be made clear from the outset that unless you spend thousands of pounds on something made with watchmaker precision, all of these devices are inherently less accurate than software equivalents. The best of them can only show planetary positions accurately over a few orbits, while software can plot positions over millions of years.

If you want to go the software route I particularly recommend the free programs Celestia and Stellarium, both available for PC and Mac, and the commercial program Red Shift for the PC. Where models score is in putting across astronomical concepts such as retrograde motion, eclipses, etc. - these things seem to be more convincing if you can actually see the geometry in three dimensions, not just on a flat screen. There are dozens of different models, with various levels of complexity and accuracy. Generally speaking, they seem to be made either as teaching tools or as ornaments and toys with a little "science" thrown in to justify their existence. For an Orrery, the main things to consider are The number of planets shown? Is our moon shown? For a Tellerium, the main things to consider are Does the Sun light up, and if so how brightly? Is it motorized or rotated by hand? Is the movement of the Moon properly geared to the movement of the Earth around the Sun? Does the movement of the Moon include some vertical variation, and variation in distance from the Earth? If not, it won't be very good for studying eclipses. Robustness etc.

I've had hands-on experience with several models, but my interest is primarily in their use as teaching tools, not ornaments or antiques. I hope to add to the list that follows if I can get a good look at more designs: Discovery World Planetarium This battery-powered motorized model is comparatively large and looks very pretty, but it's a pretty toy rather than anything like a serious model. The outer planets rotate faster than the inner ones, and after a while the arms carrying the planets sag and get in each other's way. It talks, with a button for a brief description of the sun and each planet. The planets are big and aren't to any sort of consistent scale. There should be an accompanying CD-ROM with more information on the planets. When originally sold these models were packaged with a telescope, and the list price for the pair is under £20, which is a good indication of their quality. A planetarium sold as the "University of Oxford Young Science Series Solar System" is identical, but does not include the telescope. Hamleys also appear to sell it under their own name, again without the telescope, but I have not had hands-on access; it's possible that changes have been made.

Orbit Orrery A very basic manually-moved model of the planets out to Pluto, without any gearing. The sun lights up and the Earth's moon is shown. It's well made but it's small and the specification is minimal - despite this the list price is surprising high, at around £20 from scientific instrument vendors. There are cheaper alternatives that give better value. 4M Planetarium Model A simple model kit that makes a basic Orrery. No gears, lights, or motors, but it's reasonably sized - about a foot across when built - and should be reasonably attractive if painted well. The planets vary in size, they aren't to scale but the order of size seems about right. There's no model for the moon, but in other respects it seems a good basic kit. List price is around £10 Smithsonian 3-in-1 Planetarium This is another non-motorized Orrery kit which also offers some of the features of a tellerium and a projecting star globe. The sun is big and lights up, with either an orange dome for normal use or a clear dome showing constellations. A nice touch is a second dome for the Southern hemisphere.

All nine planets are shown, with fairly long arms giving a total span of up to four feet. The planets come as unpainted white spheres, the kit includes paints and a teeny brush. One drawback is that the rings of Saturn are represented by a disc of solid plastic that looks remarkably unconvincing when painted; I ended up cutting it off and replacing it with coloured rings printed on a disc of transparent acetate sheet. The planets are sized to give an impression that Jupiter is the biggest, then Saturn, etc., but there are obvious limits to how accurate this can be at any given scale - for example, Pluto is nearly half the diameter of Earth. The Earth doesn't have a moon, but the kit includes a separate and much larger model of the Earth and Moon, which can be put onto one of the arms to show basic Earth / Moon / Sun astronomy. There's also a reasonably comprehensive manual, though the presentation isn't wonderful, and a colour guide for painting the planets. There are some nice details, such as a protective shield around the bulb which stops little fingers from damaging it while changing the domes. This version of the kit is no longer made - the current incarnation looks very similar but I'm not sure if it is identical.

When available it sold for around £15-£20. I'd say it's probably the best of these kits I've seen so far in terms of value for money. Educational Insights Geosafari Motorized Solar System This looks very similar to the Smithsonian 3-in-1 planetarium but it's a little smaller and the planets come ready painted, although not to a particularly high standard. The "motorized" part of the model is a bit of a let-down; there's no gearing at all, so all of the planets rotate at the same rate (or can be moved separately by hand). One nice feature is a 360-degree angle finder that makes it easy to set planetary positions for any given date; the instruction book gives positions from 2002 to 2005. The sun lights up fairly brightly, and a spare bulb is included, and there's a northern hemisphere star dome that can be put on in place of the yellow sun. But that's really about it for features; there's nothing like the extra Tellurium parts of the Smithsonian model, and the accompanying leaflet is only eight pages, with activities that seem to be aimed mostly at junior school level.

It's sturdily built, and if the design included gearing it would be a very nice little model. As it is the movement of the planets is misleading, a minus rather than a plus. This is still available new at around $20 in the USA, £20 in the UK. Helios Planetarium This is an excellent electrically-driven model of the classic planets out to Saturn, with relative orbit speeds reasonably accurate, aimed very much at the educational sector, secondary schools and colleges. It's typically supplied with a star dome (usually for the Northern hemisphere although a Southern dome is also available), a tool for setting the planet positions accurately and a manual of experiments and activities. Depending on what was originally sold, it may also include a larger globe of the Earth and components for using it as a Tellerium, plotting orbits of spacecraft, and other activities. It's a little on the noisy side, but hard to beat as an all-in-one solution for astronomical education. The list price is £300 (without star globe) to £400 with one star globe and all accessories.

Moon in my Room (Uncle Milton) This is a simple wall-mounted model showing the phases of the visible hemisphere of the Moon (somewhat flattened) by means of a series of lights inside the moulded plastic. There's a remote control and it can be set to cycle through the phases automatically or manually, and shut down after a set period. The full set should include the model, remote control, and a CD containing a 15-minute talk on the science. List price is £29.99 but it's available considerably cheaper on Amazon and other sites. Orbit Tellerium This hand-driven Tellerium is made mainly of plywood and is very much a teaching aid, not an ornament. It's fairly large and heavy, about 60cm long and weighing several kilos. It includes a lamp for the Sun, Earth globe, and Moon, with accurate gearing for the Moon's rotation around the Earth and the Earth around the Sun. It shows the seasons very clearly, and (with a small globe replacing the large one) does an excellent job of showing the different types of eclipse. It needs a 6V power supply for the lamp which should usually be supplied as part of the kit.

List was around £140, the current model uses more plastics. Owikit Solar System This solar-powered model kit is an interesting example of how to get things nearly right - the inner planets move faster than the outer, but they do so in pairs, not individually, with each pair always in opposition. So Venus and Mercury are always on opposite sides of the Sun, Earth is always opposite Mars, and so forth. Pluto is omitted. If you can live with its limitations it isn't bad at showing the movement of the planets (although the gear ratios are wrong for a realistic simulation of relative motion), and solar power means you'll theoretically never need batteries (but see below). This is a kit, and assembly is needed, plus simple tools including a sharp blade and something to pry the pieces apart if you get things wrong. Paints are provided. US retail price is $19.95. One thing to be aware of is that getting this to work properly requires a lot of patience; the moving parts tend to bind, and the motor has to overcome a lot of friction. It doesn't work with LED or fluorescent lights, the solar cell needs bright daylight or old-style light bulbs, which may cause problems for indoor use.

It could possibly work better with a battery instead of a solar cell, but I haven't yet tried that. Science Museum UK Glow Solar System Mobile This is exactly what it looks and sounds like - a simple mobile designed to hang over a child's bed. What may not be clear from the picture are that it's actually a fairly small mobile - the four support arms are basically straws about a foot long - and that the planets are coloured cardboard disks, not spheres.What you get is the planet disks, some cardboard stencil masks and luminous paint which can be used to make the planets glow in the dark, nylon cord, and a wall chart. Retail price from the Science Museum is £10 with some of the proceeds going to museum funds.

Tags: Build A Model Solar System + Sun, Moon & Earth Orbiter Collection | Model making - Eaglemoss Build A Model Solar System + Sun, Moon & Earth Orbiter Collection TV Ad Build a Model Earth, Moon & Sun Orbiter Each weekly issue of Build a Model Earth, Moon & Sun Orbiter comes with the components you need to build a modern version of a classical tellurion – an accurate working model of the Earth, Moon and Sun system, designed to predict solar and lunar eclipses and demonstrate the rotation and orbits of Earth and the Moon. Starting from issue 53 and complete in 52 weekly issues, each part comes with the components you need to build a beautiful working model of our home planetary system, as well as a collector’s magazine, full of in-depth features and stunning space images. Subscribe Now! Subscribe now to start building the model Orbiter To place a subscription at £7.99 per weekly issue please click Subscribe Today. Subsciption offer is only valid in the UK and Ireland.

0344 472 5264 Inside the Magazine Each week, along with the lastest parts for your model, you will receive a 24-page full colour magazine containing assembly instructions and in-depth articles about space. Detailed, step-by-step instructions for each assembly stage of the model. Our solar system Travel to the farthest reaches of the solar system. Starting from the Sun, we take you on a tour of the solar system’s marvels and mysteries. Find out all the most up-to-date information on the planets, dwarf planets, moons, asteroids and much more. Image Gallery Turn to the Image Gallery for jaw-dropping space photography and photorealistic artworks. Future issues include spectacular images from the Hubble Space Telescope as well as the biggest and best of the Earth-based observatories. The Story of Astronomy Trace the history and development of astronomy from its birth in prehistoric monuments to the high-tech science of space probes and satellites. Find out about the life and works of the greatest astronomers from Copernicus to Hawking. Star Map A new constellation with every issue, including information on all the most fascinating celestial objects found within it and practical tips on how best to observe it. Explore the night skies with specially commissioned star maps.

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Buy Now Issue 6 Magazine + Moon gear arm | Planet Venus | Tooth gear x 2 (Moon gear set) | Outsize gear axles | Venus planet arm | Screws Magazine + 85-tooth gear for the planet mars gear train Issue 16 48-Tooth Gear, Gear Collar, Plastic Washers, Self Tapping Screws, Grub Screws & Planet Spindle Issue 29 80-Tooth Gear Issue 30 Planet Gear Arm, Self-Tapping Screws, Grub Screws, 22-Tooth Gear, Gear Axle 1 & 2, 3 Base Plate Feet Issue 31 Planet Neptune, Support Arm and Neptune's Moon Issue 37 106-Tooth Gear for the Planet Neptune Gear Train Issue 38 30-Tooth Gear, Gear Collar and Planet Spindle Issue 39 98-Tooth Gear for the Planet Neptune Gear Train Issue 40 22-Tooth Gear and Gear Arm to Complete Neptune Phase Issue 41 Dwarf Planet Pluto, it's Moon Charon and Support Arm Issue 43 41-tooth gear, gear collar and planet spindle Issue 44 87-Tooth

 Gear for Pluto's Gear Train Issue 45 22-Tooth Gear for the Dwarf Planet Pluto Gear Train Issue 46 Dwarf Planet Eris, it's 106-Tooth Gear and Support Arm Issue 47 Bank Gear, Gear Collar and Planet Spindle Issue 48 Legs, Rubber Leg Pads and Allen Key Screws Issue 50 The Base Plate, Knob and Speed Control System Issue 51 Motor with Gearbox and Noise-Eliminating Foam Issue 52 AC Mains Power Adapter for your Solar System Model Go to issue (1 - 52) Go Sorry, that issue isn't available About the model Solar System A working model of the solar system as we know it Explore the mysteries of our solar system movements with this limited edition orrery, in which the movements of the planets are represented with astronomical accuracy.

Electrically powered, this attractive and completely individual piece is built to last and will become a family heirloom. Solar System Gemstone Special Edition In this special issue: A stunning set of semi-precious gemstones for your Orrery PLUS a fascinating 24 page magazine. Buy now Eyes on the skies DVD Special This special edition magazine and DVD created by the ESA/Hubble tells the story of the telescope and how it has transformed our vision of the universe. PLUS a fascinating 24 page magazine UK Telephone: 0344 472 5264 Email: solar@eaglemoss-service.com Address: Build A Precision Mechanical Solar System, Unit 4, Pullman Business Park, Pullman Way, Ringwood, Hampshire BH24 1HD Q: How much does it cost to subscribe? A: The per issue prices area as follows: Solar System UK price 99p for issue 1, £3.99 for issue and £6.99 for issue 3 to 52. Build a Model Earth, Moon & Sun Orbiter collector UK price £7.99 from issue 53 onwards. Q: What methods of payments do you accept?

A: You can pay by Direct Debit, Visa, Delta, Mastercard or Paypal. You can subscribe online via our subscription page, or call our customer services team on 0344 472 5264 in the UK to make arrangements. Q: I have not received all my issues, can you help? A: Our Customer Services Team can sort this out for you. If you email the team, please include your name and subscription reference in the subject line. Q: I have received the wrong issue/s. A: We will replace all your issues with the correct copies. Please post your incorrect copies to othe below address with a note including your name, address, subscriber number and which issues you should have received to: Build A Precision Mechanical Solar System, Database Factory,Unit 4, Pullman Business Park, Pullman Way, Ringwood, Hampshire BH24 1HD. Alternatively you can call or email our Customer Services Teams. Q: How do I cancel my subscription?

A: You can cancel at any time giving 28 days notice – please write to us at: Build A Precision Mechanical Solar System, Database Factory,Unit 4, Pullman Business Park, Pullman Way, Ringwood, Hampshire BH24 1HD. You can also email or call our Customer Services Teams. We just ask that you use up any remaining credit on your account. Q: How does the premium subscription work? A: The premium subscription is an exclusive offer giving you the opportunity to receive additional gifts throughout the collection by paying only £1.00 (Eire €1.50) extra per issue. That means as a premium subscriber you will get all of the benefits of a regular subscription, plus you receive the telescope and the planisphere. This offer is subject to availability while stock lasts. Q: If I take out a premium subscription do I still receive the other FREE subscription gifts? A: Yes, as a premium subscriber you will receive 5 free gifts PLUS the telescope and the planisphere. This offer is subject to availability while stock lasts. Q: I can't find copies in the shops – help!

A: You can ask your newsagent to place a regular order for you so you can pick up your issues from them. If you need back copies you can ask your newsagent to order them for you or just contact our Customer Services Team. Q: I can't get through on the phone number given. A: We have several lines dedicated to helping you, but they can be busy at peak times so please keep trying. Alternatively, please email our customer services team on: solar@eaglemoss-service.com . Q: How can I get back copies? A: You can order back copies via newsagents, our online shop, or if you prefer you can call our Customer Services department to order. Q: What day is the collection on sale? A: Every Thursday. Q: How can I get copies if I live outside the UK? A: I’m sorry, this updated collection is only available in the UK and Eire at the moment. Q: I can’t see some of the pages on the website. Help! A: It may be a temporary problem, so please click Refresh to reload the page.

If you are experiencing problems getting through to the secure order area when trying to place a subscription order, please email us on the customer service website enquiry email address. Q: How many issues is my model solar system complete in? A: Your model solar system will be complete in 52 issues. From issue 53 onwards, you will be able to build a Sun, Moon & Earth Orbiter’ Q: Help! I’m struggling to build my model solar system. A: We have assembly videos on our website to help you build your model solar system. If you have any further questions, don’t hesitate to contact customer services. Orrery - definition of orrery by The Free Dictionary Orrery - definition of orrery by The Free Dictionary Also found in: Thesaurus , Encyclopedia , Wikipedia . or·re·ry n. pl. or·re·ries A mechanical model of the solar system or parts of it.

[After Charles Boyle, Fourth Earl of Orrery (1676-1731), for whom one was made.] orrery (ˈɒrərɪ) n, pl -ries (Astronomy) a mechanical model of the solar system in which the planets can be moved at the correct relative velocities around the sun [C18: originally made for Charles Boyle, Earl of Orrery] or•rer•y (ˈɔr ə ri, ˈɒr-) n., pl. -rer•ies. an apparatus for representing with movable balls the positions, motions, and phases of the bodies of the solar system. [1705–15; after Charles Boyle, Earl of Orrery (1676–1731), for whom it was first made] ThesaurusAntonymsRelated WordsSynonymsLegend: Noun 1.

orrery - planetarium consisting of an apparatus that illustrates the relative positions and motions of bodies in the solar system by rotation and revolution of balls moved by wheelwork; sometimes incorporated in a clock planetarium - an apparatus or model for representing the solar systems Translations Solar System Model - the Orrery | The Eli Whitney Museum and Workshop Solar System Model - the Orrery Eli Whitney Museum Theme: Natural History Description Models organize big ideas for scientists and students; they identify and test questions and are ideal tools for thinking. The Earth/Moon Rotation orrery shows our planetary movement around the sun and demonstrates lunar orbit and moon phases when illuminated with an accompanying light. Meets Connecticut Science Standards 5.3 : Most objects in the solar system are in a regular and predictable motion. 6.3 : Variations in the amount of the sun’s energy hitting the Earth’s surface affect daily and seasonal weather patterns. 8.3 : The solar system is composed of planets and other objects that orbit the sun. Meets Common Core Standards 5-ESS1 : Earth's Place in the Universe MS-ESS1 : Earth's Place in the Universe A model of the sun, the earth, and the inner planets:to guide your observations, to share the power of models for thinking.

All the Parts; no tools required. The Orrery Isaac Newton (1642 - 1727) worked out the mathematics of the movement of the planets. Charles Boyle, the Earl of Orrery, commissioned George Graham to build a mechanical model of Newton's Ideas in 1700. Orrery's name stuck. A Learning Tool When Eli Whitney went to Yale in 1788, science as a subject was still new. The first Orrery purchased by Yale arrived from Germany broken. Whitney fixed it, a hint of the practical mechanical skills that would make him famous. Models All models are imperfect. This model shows the size of Mercury, Venus, Earth and the Moon relative to each other. Does the Sun fit that Scale? Can you find how many times larger than the earth the sun is? What color are the planets in our model? This Model shows that the Earth is about 3 times as far away from the sun as Mercury. But the Earth is 12,000 Earth diameters away from the Sun (12,000 x 3/4" = 9000 inches or about 750 feet.) How far should Mercury be from the Sun?

Some solar models show why we experience the seasons. This one doesn't. Why not? Questions These challenges will start you experimenting. discuss the problems with your friends. Find more here . Where in the World are you: Decorate the Earth. Make a small mark to show where you are. Does your location matter in how will you see Mercury? Will it change the stars you see? Glossary: remember the facts. Number of hours in a day: Demonstrate a day. Number of days in a month: Demonstrate a month. Number of months in a year: Demonstrate a year. Will this model show days accurately? Next Challenges: Demonstrate an eclipse of the sun. Demonstrate a full moon. Demonstrate a full moon. The Earth travels around the Sun in approximately 365 ¼ days. How long does the Moon take to revolve around the earth? Answer: Approximately 28 days pass between a full moon and the next one, but the answer may not be that simple. During a full moon the earth and the moon line up on a radius drawn from the sun through the Earth. During those twenty-eight days the Earth has progressed 15 degrees further alone its orbit around the sun.

Therefore, between full moons the Moon has traveled 360 degrees around the earth plus the 15 degrees that the earth has moved. (minus 15 degrees, if the orbit of the moon is opposite the orbit of the Earth) A more correct answer may be 27 days or 29 days dependent on the direction of the orbits. The same side of the Moon is always facing the Earth. Does the Moon spin on it axis? How fast, if at all? Answer: In order for the same side of the moon to face us, the Moon must rotate at the same rate that it orbits the Earth. From full moon to full moon is 29.5 days or 12.3 times in a year. The Earth orbits once in a year, which must be added to the moon’s revolution, so in the end the Moon rotates 13.3 times in a year. The base of the orrery has four sides. Could those sides represent the four seasons? Answer: Yes, the four sides of the base model the four seasons very well. When viewed from the Earth’s North Pole, the Earth moves in a counter-clockwise direction.

Therefore, the sides of the base should be labeled winter, spring, summer and fall in a clock-wise order. Are the relative sizes of the moon, the planets and the sun accurate? Answer: Oh, no. The Earth is modeled with a 0.9-inch diameter ball. Venus is just about the same size as the Earth and so it makes sense that it is a 0.9-inch ball as well. Mercury has a diameter that is 40% of Earth, so using the same scale it should have a diameter of .4 x .9 or 0.36-inch. The actual size of the Mercury model in 0.4 inches, which is only slightly larger than it should be. The Moon should be 27% of the Earth and it measures 0.25 inches. 0.27 x 0.9 = 0.24. That dimension is very close to the size it should be. Now, the Sun… The actual Sun is 110 times larger in diameter than the Earth. So if the Earth is 0.9 inches, the Sun should be 99 inches in diameter. Wow!

The Sun should be a ball a little over eight feet in diameter (the height of most ceilings). The model is way too small for the Sun. Are the distances accurate? Answer: The reported distances of the planets from the Sun are: Earth - 149 million kilometers, Venus – 108, Mercury – 58. The distance from the Earth to the Moon is 0.38 million kilometers. On the model the distance from the Sun to the Earth is 7.5 inches. Students can use proportions to verify the following dimensions for the model. Sun to Mercury should be 3 inches and the Sun to Venus should be 5 ¼ inches. Using this same proportion, the distance from the Earth to the Moon should be only 0.019 inches (less than 1/32nd of an inch). This dimension is not scaled correctly at all. A day is 24 hours long. Does this fact mean that the earth rotates exactly 360 degrees in 24 hours? Answer: Well, not exactly… The earth actual rotates 360 degrees in 4 minutes less than 24 hours.

The reason for this effect is that the Earth is moving one degree each day in its orbit around the Sun. The Earth has to rotate 361 degrees between noon on one day to noon on the next day. The 360-degree rotation is called the sidereal day. Textbooks usually describe the periods of rotation and revolution for the planets and the moon, but rarely do they identify the direction of movement. Can you make observations or plan experiments to determine which way the moon orbits the Earth? .... which way the Earth obits the Sun? Answer: You can determine the direction of rotation of the Earth without setting up an experiment. The sun rises in the East. Therefore, the Earth must spin counter-clockwise when viewed from the North Pole. Using your orrery mark a position on the Earth. Mark the direction toward the East. Spin the Earth in both directions and determine which direction shows the Sun in the East when the position moves from what would be the dark half (night) to the light half (day). Figuring out the direction of orbit for the Moon may be a little more difficult. In the evening set up a stick or series of two sticks that point at the Moon. Record the time.

On the next night (or subsequent nights) at the same time of day determine whether the Moon is at the same position or further to the East or West. You should observe that the Moon is further to the East. Accordingly, the Moon will rise later each night. It orbits the Earth in a counter-clockwise sense. You can determine the direction of Earth’s orbit similarly by observing the movement of the stars from night to night. You should pick a star that is in the Eastern or Western sky. Measure whether the star moves to the East or the West. You should find that the stars move toward the West indicating that the Earth’s orbit in also counter-clockwise. This experiment requires more precise measurement and often many days between readings. Remember the Earth only moves one degree each day in its trip around the Sun. Do you see a pattern? Most everything rotates or revolves in a counter-clockwise direction in our solar system, but not everything. Venus spins clockwise or retrograde. Can you give an explanation? Is there "day" and "night" (a period of light followed by a period of dark) on the moon? How long is a "Moon day?" Answer: The moon has day and night just like on Earth.

However, each lasts for about 15 days on the moon. A "Moon day" last 29.5 days. The tides are predominately caused by the motion of the Moon. The Earth rotates approximately once every 24 hours. Yet, if a high tide is at 9am one day, on the next day there will be a high tide at about 10am. How could this be? Answer: The oceans of the Earth are pulled toward the Moon. When the Earth spins each day, the Moon moves around in its orbit too. When combining both effects, a position on the Earth points toward the Moon once every 25 hours instead of every 24. For this reason the tides are approximately one hour later each day. There are usually two sets of tides each day. The second set of tides is a rebounding phenomenon due to the specific shape and size of our oceans. The arms that support Earth, Mercury and Venus are fixed length. Is this accurate? Answer: Yes. The orbits of most of the planets including all the inner planets are very circular. What causes the earth to have different seasons? Is this characteristic accurately modeled with this Orrery?

Answer: The seasons on Earth are caused by the tilt of its axis relative to its orbit. The direction of the tilt stays the same relative to the stars as the earth orbits around the Sun. In this way the North Pole leans toward the Sun in summer and away from the Sun in winter. During summer in the Northern Hemisphere there are more daylight hours and the Sun is more perpendicular (more overhead). The seasons are NOT caused by the Earth moving closer and further away from the Sun. This orrery does not model the tilt of the earth. From antiquity the circle has always had 360 degrees. What did one degree represent? Answer: One degree represents the angle the Earth travels around the Sun in one day. In summer daylight lasts longer. In winter nighttime is longer. Is this true in the Southern Hemisphere as well? Is there any place on Earth where the amount of daylight does’t change throughout the year? Answer: Sunlight falls on half the Earth. The other half is in darkness. The line marking the boundary between the two is a circle perpendicular to the line connect the Earth with the Sun.

Because the axis of the Earth’s rotation is tilted some 23 ½ degrees, the North and South Poles are not usually on this boundary circle. In summer the North Pole is in the sunlight side and any place in the Northern Hemisphere will spend more than half a day in the sunlight side. In fact there will be no nighttime at the North Pole at all. While the North is in summer the Southern Hemisphere will be in winter and nighttime will be longer than half a day. The affect of the tilt on the length of sunlight decreases toward the equator until when you are on the equator. At the equator daylight and nighttime are both 12 hours all year long. In the United States the Sun rises in the East and sets in the West. In Australia are those directions reversed? Answer: No. The Sun everywhere on Earth rises in the East and sets in the West. What is different is where the Sun appears in the sky. In the United States the Sun is in the southern half of the sky. In Australia the Sun is in the Northern half. Venus, and especially Mercury, either set in the West soon after dusk or rise in the East just before dawn. They never appear in the night sky directly over head.

Why is that? Answer: The orbits of both Mercury and Venus are inside the orbit of Earth. As those two planets travel around the Sun, the furthest they can appear away from the Sun is when their position in their orbit is perpendicular to Earth. In this position Venus has a maximum angle of 35 degrees from the Sun and Mercury has a maximum angle of 21 degrees. If the Sun was just on the horizon, the highest Venus could be is 35 degrees up. In reality, to view the Stars and the Planets, the Sun must have set for some period of time – about an hour or so. An hour relates to 15 degrees of the Earth’s rotation. When that 15 degrees is factored in, the result is that Venus is not seen higher than about 20 degrees and mercury not higher than 5 degrees. By the way, you can tell the difference between the stars and the planets, because the planets all track in the same area as the Sun and the Moon (called the ecliptic) and the planets don’t twinkle. When there is a "new moon," will the lit section of the moon be on the East or West section of the moon.

Answer: Knowing that counter-clockwise is the direction for both Earth’s spin and the Moon’s orbit, you can place the Moon in a position where it is just visible at dusk. The lit side of the Moon will be towards the West. What are the positions of the Earth and the Moon when there is an eclipse of the Sun? Answer: The Moon will between the Earth and the Sun. What are the positions of the Earth and the Moon when there is an eclipse of the Moon? Answer: The Earth will between the Moon and the Sun. Where are the Earth and the Moon when there is a Full Moon? If you are on the Moon where are their positions when there is a "Full Earth?" Answer: In a full moon the Moon will be away from the Sun so the Earth will see the whole sunlit side. This position is same as in an eclipse of the Moon. However, an eclipse does not occur every time there is a full moon. The orbit of the Moon wobbles up and down. An eclipse will only occur when the Moon is directly in line with the Earth. Why are shadows longer in the winter than in the summer? Answer: In winter the tilt of the Earth is pointed away from the Sun.

The Sun will be lower in the sky and shadows will be longer. The earth in this model is ¾ inch in diameter. If the Sun were modeled to this same scale, how big would it be?

Question: What name is given to a mechanical model of the Solar System?
Answer: Orrery